Heater

It's in. The easy part was wiring the new ceramic core and making a plate for it to sit in... The hard part was replacing all the rotted foam in the poor old thing. It looked/felt like it had been doused in gas - all the foam would come apart at the slightest touch.
I replaced all the foam with adhesive backed foam strips used to hold truck caps down with. Perhaps not going to pass concours, but good enough for me.

The new heater core

My sketchy re-foaming. The whole unit had to come apart to get the inner vents...

Back in place. The dash will be in tonight, and then I'll get the instrument cluster re-wired for my ammeter and voltmeter.